Predischarge non-invasive risk assessment for prediction of significant hyperbilirubinemia in term and late preterm neonates

Validating the early phototherapy prediction tool across cohorts

Background

Hyperbilirubinemia of the newborn infant is a common disease worldwide. However, recognized early and treated appropriately, it typically remains innocuous. We recently developed an early phototherapy prediction tool (EPPT) by means of machine learning (ML) utilizing just one bilirubin measurement and few clinical variables. The aim of this study is to test applicability and performance of the EPPT on a new patient cohort from a different population.

Materials and methods

This work is a retrospective study of prospectively recorded neonatal data from infants born in 2018 in an academic hospital, Regensburg, Germany, meeting the following inclusion criteria: born with 34 completed weeks of gestation or more, at least two total serum bilirubin (TSB) measurement prior to phototherapy. First, the original EPPT-an ensemble of a logistic regression and a random forest-was used in its freely accessible version and evaluated in terms of the area under the receiver operating characteristic curve (AUROC). Second, a new version of the EPPT model was re-trained on the data from the new cohort. Third, the predictive performance, variable importance, sensitivity and specificity were analyzed and compared across the original and re-trained models.

Results

In total, 1,109 neonates were included with a median (IQR) gestational age of 38.4 (36.6-39.9) and a total of 3,940 bilirubin measurements prior to any phototherapy treatment, which was required in 154 neonates (13.9%). For the phototherapy treatment prediction, the original EPPT achieved a predictive performance of 84.6% AUROC on the new cohort. After re-training the model on a subset of the new dataset, 88.8% AUROC was achieved as evaluated by cross validation. The same five variables as for the original model were found to be most important for the prediction on the new cohort, namely gestational age at birth, birth weight, bilirubin to weight ratio, hours since birth, bilirubin value.

Discussion

The individual risk for treatment requirement in neonatal hyperbilirubinemia is robustly predictable in different patient cohorts with a previously developed ML tool (EPPT) demanding just one TSB value and only four clinical parameters. Further prospective validation studies are needed to develop an effective and safe clinical decision support system.

Universal screening for hyperbilirubinemia in term healthy newborns at discharge: A systematic review and meta-analysis

Background

All term healthy neonates are screened for jaundice before hospital discharge as a standard clinical practice, but methods vary from clinical screening (visual inspection and/or risk factor assessment) to transcutaneous bilirubin (TcB) or total serum bilirubin (TSB) testing, depending on the setting.

Methods

This systematic review of randomized and non-randomized studies evaluated the effectiveness of universal TcB and universal TSB screening at discharge compared to clinical screening alone for term healthy neonates. The outcomes were neonatal mortality, readmission for jaundice, severe hyperbilirubinemia (>20 mg/dL), jaundice requiring exchange transfusion, and bilirubin-induced neurological dysfunction (BIND). We searched MEDLINE via Ovid, EBM reviews, Embase, CINAHL, clinical trials databases, and reference lists of retrieved articles. Two authors separately evaluated the risk of bias, extracted data, and synthesized effect estimates using relative risk (RR) for randomized and odds ratio (OR) for non-randomized studies.

Results

For universal TcB at discharge, we included one randomized trial enrolling 1858 participants and four non-randomized studies enrolling 375 956 participants. No study reported neonatal mortality. The randomized trial suggested that universal TcB at discharge may decrease readmission for jaundice (risk ratio (RR) = 0.24, 95% confidence interval (CI) = 0.13 to 0.46; low certainty evidence) and severe hyperbilirubinemia (RR = 0.27, 95% CI = 0.08 to 0.97; low certainty evidence), but the effect on jaundice requiring exchange transfusion (RR = 0.20, 95% CI = 0.01 to 41.6) and BIND (RR = 0.33, 95% CI = 0.01 to 8.17) was uncertain. Meta-analysis of non-randomized studies suggested that TcB may decrease severe hyperbilirubinemia (odds ratio (OR) = 0.25, 95% = CI 0.12 to 0.52; low certainty evidence) and jaundice requiring exchange transfusion (OR = 0.28, 95% CI = 0.19 to 0.42; low certainty evidence), but the effect on readmission for jaundice was uncertain (OR = 1.01, 95% CI = 0.38 to 2.7; very low certainty evidence). For universal TSB, we included three studies from the United States enrolling 490 426 participants. The effect on severe hyperbilirubinemia (OR = 0.37, 95% CI = 0.15 to 0.88), jaundice requiring exchange transfusion (OR = 0.53, 95% CI = 0.13 to 2.25) and readmission for jaundice (OR = 1.01, 95% CI = 0.62 to 1.67) was uncertain.

Conclusions

Universal TcB at discharge may improve clinical outcomes for term healthy neonates. Evidence for universal TSB is uncertain.

Registration

PROSPERO 2020 CRD42020187279.

Predicting the Need for Phototherapy After Discharge

BACKGROUND AND OBJECTIVES

Bilirubin screening before discharge is performed to identify neonates at risk for future hyperbilirubinemia. The American Academy of Pediatrics recommends using a graph of bilirubin levels by age (the Bhutani Nomogram) to guide follow-up and a different graph to determine phototherapy recommendations. Our objective was to evaluate predictive models that incorporate the difference between the last total serum bilirubin (TSB) before discharge and the American Academy of Pediatrics phototherapy threshold (Δ-TSB) to predict a postdischarge TSB above the phototherapy threshold by using a single graph.

METHODS

We studied 148 162 infants born at ≥35 weeks' gestation at 11 Kaiser Permanente Northern California facilities from 2012 to 2017 whose TSB did not exceed phototherapy levels and who did not receive phototherapy during the birth hospitalization. We compared 3 logistic models (Δ-TSB; Δ-TSB-Plus, which included additional variables; and the Bhutani Nomogram) by using the area under the receiver operating characteristic curve (AUC) in a 20% validation subset.

RESULTS

A total of 2623 infants (1.8%) exceeded the phototherapy threshold postdischarge. The predicted probability of exceeding the phototherapy threshold after discharge ranged from 56% for a predischarge Δ-TSB 0 to 1 mg/dL below the threshold to 0.008% for Δ-TSB >7 mg/dL below the threshold. Discrimination was better for the Δ-TSB model (AUC 0.93) and the Δ-TSB-Plus model (AUC 0.95) than for the Bhutani Nomogram (AUC 0.88).

CONCLUSIONS

The use of Δ-TSB models had excellent ability to predict postdischarge TSB above phototherapy thresholds and may be simpler to use than the Bhutani Nomogram.

Hyperbilirubinemia in Preterm Infants Admitted to Neonatal Intensive Care Units in Ethiopia

Background. Hyperbilirubinemia is prevalent and protracted in preterm infants. This study assessed the pattern of hyperbilirubinemia in preterm infants in Ethiopia. Methods. This study was part of multi-centered prospective, cross-sectional, observational study that determined causes of death among preterm infants. Jaundice was first identified based on clinical visual assessment. Venous blood was then sent for total and direct serum bilirubin level measurements. For this study, a total serum bilirubin level ≥5 mg/dL was taken as the cutoff point to diagnose hyperbilirubinemia. Based on the bilirubin level and clinical findings, the final diagnoses of hyperbilirubinemia and associated complications were made by the physician. Result. A total of 4919 preterm infants were enrolled into the overall study, and 3852 were admitted to one of the study’s newborn intensive care units. Of these, 1779 (46.2%) infants were diagnosed with hyperbilirubinemia. Ten of these (0.6%) developed acute bilirubin encephalopathy. The prevalence of hyperbilirubinemia was 66.7% among the infants who were less than 28 weeks of gestation who survived. Rh incompatibility (P = .002), ABO incompatibility (P = .0001), and sepsis (P = .0001) were significantly associated with hyperbilirubinemia. Perinatal asphyxia (P-value = 0.0001) was negatively associated with hyperbilirubinemia. Conclusion. The prevalence of hyperbilirubinemia in preterm babies admitted to neonatal care units in Ethiopia was high. The major risk factors associated with hyperbilirubinemia in preterm babies in this study were found to be ABO incompatibility, sepsis, and Rh isoimmunization.

Clinical predictive score of predischarge screening for severe hyperbilirubinemia in late preterm and term infants

BACKGROUND

Early identification and appropriate follow-up of infants at risk of severe hyperbilirubinemia are part of preventing complications. This study aims to develop the clinical predictive score to predict subsequent severe hyperbilirubinemia in healthy Thai infants.

METHODS

A case-control study was conducted using medical records of 147 hyperbilirubinemia cases and 147 age-matched controls among healthy late preterm and term Thai newborn infants during January 2015 and December 2016. The routinely measured TcB values at 48-54 hours of age and all predischarge clinical characteristics were collected. Multivariable logistic regression was used to find a clinical prediction model to predict subsequent severe hyperbilirubinemia within 7 days after birth which defined as a postdischarge bilirubin level exceeding the hour-specific recommended threshold for phototherapy by the American Academy of Pediatrics (AAP).

RESULTS

The best clinical predictors for subsequent severe hyperbilirubinemia were TcB values at 48-54 hours and gestational age of infants. Predischarge TcB at 48-54 hours of life was classified into 3 levels: < 10 mg/dL, 10-12 mg/dL and > 12 mg/dL. Gestational age was categorized into 5 groups. The risk score derived from these 2 significant factors predicted subsequent severe hyperbilirubinemia with an AuROC curve of 81.0% (95% CI: 76.2-85.9%) in 3 risk group, high, moderate and low. The positive likelihood ratio for subsequent severe hyperbilirubinemia of the high-risk group (score > 5) was 4.53 (95% CI: 2.91-7.04) with specificity of 87.1%. The negative predictive value of low-risk group (score < 3) was 81%.

CONCLUSIONS

A simple predischarge prediction score using gestational age and TcB values at 48-54 hours of life was developed. This score classified late preterm and term newborn infants into 3 distinct risk levels and may be useful to identify high-risk infants for outpatient follow-up of subsequent severe hyperbilirubinemia.

Transcutaneous bilirubin nomogram for the first 144 hours in Thai neonates

Objectives: To develop an hour-specific transcutaneous bilirubin (TcB) nomogram for Thai neonates and to compare the ability of this nomogram with that of Bhutani's total serum bilirubin (TSB) nomogram for prediction of significant hyperbilirubinemia requiring phototherapy.Methods: Healthy Thai neonates, gestational age ≥35-week-gestation and birth weight ≥2000 grams were enrolled. Neonates who could not attend the postdischarge follow-up at our center were excluded. TcB measurements were routinely performed at 6 am and 6 pm using JM103 transcutaneous bilirubinometer until the neonates were discharged or received phototherapy. TcB levels were also measured at least once during 24-72 hours after discharge and thereafter depending on the pediatricians' decision. The nomogram was developed from the TcB data during age 12-144 hours of neonates who did not require phototherapy. The TcB values that obtained predischarge or before receiving phototherapy of all neonates were used to determine the predictive ability of this nomogram and Bhutani's TSB nomogram.Results: A total of 1071 neonates were included. Two hundred forty-one neonates (22.5%) required phototherapy. The nomogram was constructed using 4834 hour-specific TcB values. It provided a good prediction with the area under curve (AUC) of 0.89. The 75th percentile tract revealed sensitivity and negative predictive value (NPV) of 87.1 and 95.4% while that of the 40th percentile tract were 97.9 and 98.5% respectively. When Bhutani's nomogram was used, the AUC was 0.84. The sensitivity and NPV of the 75th percentile tract were 56.4 and 88.2%, and for the 40th percentile tract were 97.1 and 98.0% respectively.Conclusion: The newly developed TcB nomogram revealed slightly better predictive ability than Bhutani's TSB nomogram for term and late preterm Thai neonates who were the population with high prevalence of significant hyperbilirubinemia. The 40th percentile curve of both nomograms should be considered as an appropriate cut-off level for prediction.

Do triple test results predict risk for neonatal hyperbilirubinemia?

Objective:

Neonatal jaundice is the most common condition that requires hospital admission and outpatient follow-up after discharge in neonates. The values of more than 17 mg/dL in term infants are accepted as neonatal significant hyperbilirubinemia. We aimed to define if there is any relationship between second trimester serum markers and neonatal severe hyperbilirubinemia to protect the neonates from its neurological damage.

Methods:

Total 1372 pregnant women were enrolled who had done triple test between April 2014 and 2015 and then given birth at our hospital. Our primary outcome was neonatal significant hyperbilirubinemia.

Results:

The mean age of our study population was 27.9±5.6. A total of 59 patients had babies with neonatal hyperbilirubinemia after exclusion of Rh incompatibility. We detected that the presence of in vitro pregnancy, maternal health problems or poor obstetric history had no effect on the risk for neonatal hyperbilirubinemia. Neonatal hyperbilirubinemia was related with low E₃ levels. The ratios of AFP/E₃ and hCG/E₃ were the most helpful to predict the neonatal hyperbilirubinemia.

Conclusions:

According to our results, low E₃ levels in the triple test result can be helpful to predict the development of the neonatal hyperbilirubinemia. However, this is a bit expensive and many developing countries may not afford it.

Transcutaneous bilirubin measurement to estimate serum bilirubin in neonates in a multi-ethnic cohort: a literature review

Neonatal jaundice (NNJ) is common in Singapore and is usually monitored with serum bilirubin (SB). This paper reviews literature on the accuracy of transcutaneous bilirubin (TcB) measurement compared to SB to monitor jaundice in neonates of major ethnic groups of Singapore, i.e. Chinese, Malay, and Indian. 15 studies with Chinese babies, 5 with Malay babies, and 15 with Indian babies were identified (total of 28 articles, some with more than one race). Correlation coefficient is good for all three races. Chest is a better site for TcB measurement than forehead, though both are good. Infants with TcB levels more than 160–200 μmol/L should have SB checked. While post-phototherapy infants may benefit from TcB 24 hours after cessation of phototherapy, more needs to be done to ascertain its usefulness. Premature babies should have SB measurements. TcB measurement is suitable to monitor NNJ in term and healthy Chinese, Malay, and Indian babies.

Risk factors for severe neonatal hyperbilirubinemia in low and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Available evidence suggests that low- and middle-income countries (LMICs) bear the greatest burden of severe neonatal hyperbilirubinemia characterized by disproportionately high rates of morbidity, mortality and neurodevelopmental disorders compared to high-income countries. We set out to identify the risk factors that contribute to the burden of severe hyperbilirubinemia in the most developmentally disadvantaged LMICs to highlight areas for action and further research.

METHODS

We systematically searched PubMed, Scopus, Ovid EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), WHO Library Database (WHOLIS), African Index Medicus (AIM), African Journals Online (AJOL), LILACS, and IndMed for reports published between January 1990 and June 2014. We included only studies that controlled for the effects of confounding variables in determining maternal and infant risk factors for severe hyperbilirubinemia. We conducted meta-analysis of the eligible studies and computed the summary risk estimates with random effects models.

RESULTS

A total of 13 studies with 1,951 subjects and 32,208 controls from India, Nigeria, Pakistan, Nepal and Egypt were identified and analyzed. The pooled data showed that primiparity (OR, 1.59; 95% CI:1.26-2.00), delivery outside public hospitals (OR, 6.42; 95% CI:1.76-23.36), ABO incompatibility (OR, 4.01; 95% CI:2.44-6.61), Rhesus hemolytic disease (OR, 20.63; 95% CI:3.95-107.65), G6PD deficiency (OR, 8.01; 95% CI:2.09-30.69), UGT1A1 polymorphisms (OR, 4.92; 95% CI:1.30-18.62), low gestational age (OR, 1.71; 95% CI:1.40-2.11), underweight/weight loss (OR, 6.26; 95% CI:1.23-31.86), sepsis (OR, 9.15; 95% CI:2.78-30.10) and high transcutaneous/total serum bilirubin levels (OR, 1.46; 95% CI:1.10-1.92) placed infants at increased risk of severe hyperbilirubinemia or bilirubin induced neurologic dysfunctions. Low social class was not associated with an increased risk of severe hyperbilirubinemia.

CONCLUSIONS

Infants at risk of severe hyperbilirubinemia in LMICs are associated with maternal and neonatal factors that can be effectively addressed by available interventions to curtail the disease burden prevailing in the affected countries.

Transcutaneous bilirubinometry

Although the modern era of transcutaneous bilirubin monitoring (TcB) began only about 35 years ago, this screening tool is now widely used in newborn nurseries and outpatient clinics, offices, and emergency departments to obtain a rapid and non-invasive estimate of the degree of hyperbilirubinemia. TcB devices have become more sophisticated, and major breakthroughs include the following: (a) ability to report a bilirubin value rather than an index value, (b) enhanced correction for chromophores other than bilirubin, and (c) technologic improvements including interface with electronic medical records. Good agreement with laboratory bilirubin measurement has been demonstrated, and the ability of TcB screening to predict and decrease the incidence of subsequent hyperbilirubinemia has been well-documented. To date, it has not been shown that this screening results in improved long-term outcomes.

Bilirubin nomograms for identification of neonatal hyperbilirubinemia in healthy term and late-preterm infants: a systematic review and meta-analysis

BACKGROUND

Hyperbilirubinemia occurs in most healthy term and late-preterm infants, and must be monitored to identify those who might develop severe hyperbilirubinemia. Total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) nomograms have been developed and validated to identify neonatal hyperbilirubinemia. This study aimed to review previously published studies and compare the TcB nomograms with the TSB nomogram, and to determine if the former has the same predictive value for significant hyperbilirubinemia as TSB nomogram does.

METHODS

A predefined search strategy and inclusion criteria were set up. We selected studies assessing the predictive ability of TSB/TcB nomograms to identify significant hyperbilirubinemia in healthy term and late-preterm infants. Two independent reviewers assessed the quality and extracted the data from the included studies. Meta-Disc 1.4 analysis software was used to calculate the pooled sensitivity, specificity, and positive likelihood ratio of TcB/TSB nomograms. A pooled summary of the receiver operating characteristic of the TcB/TSB nomograms was created.

RESULTS

After screening 187 publications from electronic database searches and reference lists of eligible articles, we included 14 studies in the systematic review and meta-analysis. Eleven studies were of medium methodological quality. The remaining three studies were of low methodological quality. Seven studies evaluated the TcB nomograms, and seven studies assessed TSB nomograms. There were no differences between the predictive abilities of the TSB and TcB nomograms (the pooled area under curve was 0.819 vs. 0.817).

CONCLUSIONS

This study showed that TcB nomograms had the same predictive value as TSB nomograms, both of which could be used to identify subsequent significant hyperbilirubinemia. But this result should be interpreted cautiously because some methodological limitations of these included studies were identified in this review.

Validation of transcutaneous bilirubin nomogram for identifying neonatal hyperbilirubinemia in healthy Chinese term and late-preterm infants: a multicenter study

OBJECTIVE

to prospectively validate a previously constructed transcutaneous bilirubin (TcB) nomogram for identifying severe hyperbilirubinemia in healthy Chinese term and late-preterm infants.

METHODS

this was a multicenter study that included 9,174 healthy term and late-preterm infants in eight hospitals of China. TcB measurements were performed using a JM-103 bilirubinometer. TcB values were plotted on a previously developed TcB nomogram, to identify the predictive ability for subsequent significant hyperbilirubinemia.

RESULTS

in the present study, 972 neonates (10.6%) developed significant hyperbilirubinemia. The 40(th) percentile of the nomogram could identify all neonates who were at risk of significant hyperbilirubinemia, but with a low positive predictive value (PPV) (18.9%). Of the 453 neonates above the 95(th) percentile, 275 subsequently developed significant hyperbilirubinemia, with a high PPV (60.7%), but with low sensitivity (28.3%). The 75(th) percentile was highly specific (81.9%) and moderately sensitive (79.8%). The area under the curve (AUC) for the TcB nomogram was 0.875.

CONCLUSIONS

this study validated the previously developed TcB nomogram, which could be used to predict subsequent significant hyperbilirubinemia in healthy Chinese term and late-preterm infants. However, combining TcB nomogram and clinical risk factors could improve the predictive accuracy for severe hyperbilirubinemia, which was not assessed in the study. Further studies are necessary to confirm this combination.

Physiologic underpinnings for clinical problems in moderately preterm and late preterm infants

This article highlights some of the important developmental characteristics that underpin common problems seen in moderate and late preterm infants. Preterm birth is associated with an increased prevalence of clinical problems caused by functional immaturities in a wide variety of organ systems, acquired problems, and problems associated with inadequate monitoring and/or follow-up plans. There are variations in the degree of maturation among infants of similar gestational ages because the developmental process is nonlinear. Therefore, different organ systems mature at rates and trajectories that are specific to their functions. A better understanding of these principles can help guide optimal treatment strategies.

Incidence of and risk factors for neonatal jaundice among newborns in southern Nepal

OBJECTIVE

To quantify the incidence of and risk factors for neonatal jaundice among infants referred for care from a rural, low-resource, population-based cohort in southern Nepal.

METHODS

Study participants were 18,985 newborn infants born in Sarlahi District in southern Nepal from May 2003 through January 2006 who participated in a cluster-randomised, placebo-controlled, community-based trial to evaluate the effect of newborn chlorhexidine cleansing on neonatal mortality and morbidity. Jaundice was assessed based on visual assessment of the infant by a study worker and referral for care. Adjusted relative risks (RR) were estimated to identify risk factors for referral for neonatal jaundice using Poisson regression.

RESULTS

The incidence of referral for neonatal jaundice was 29.3 per 1000 live births (95% confidence interval: 26.9, 31.7). Male sex, high birth weight, breastfeeding patterns, warm air temperature, primiparity, skilled birth attendance, place of delivery, prolonged labour, oil massage, paternal education and ethnicity were significant risk factors (P-values < 0.01). After multivariable adjustment, sex, birth weight, difficulty feeding, prolonged labour, primiparity, oil massage, ambient air temperature and ethnicity remained important factors. Among infants with difficulty feeding, exclusive breastfeeding was a risk factor for neonatal jaundice, whereas exclusive breastfeeding was protective among infants with no report of difficulty feeding.

CONCLUSIONS

Several known risk factors for neonatal jaundice in a low-resource setting were confirmed in this study. Unique observed associations of jaundice with ambient air temperature and oil massage may be explained by the opportunity for phototherapy based on the cultural practices of this study population. Future research should investigate the role of an infant's difficulty in feeding as a potential modifier in the association between exclusive breastfeeding and jaundice.